Update lerna (#5262)

* update lerna

* Update yarnrc

.yarnrc

@@ -1,4 +1,2 @@
 yarn-path "./jupyterlab/staging/yarn.js"
-workspaces-experimental true
-registry "https://registry.npmjs.org"
 ignore-optional true

lerna.json

@@ -1,12 +1,6 @@
 {
-  "lerna": "2.4.0",
+  "lerna": "3.2.1",
   "version": "independent",
   "npmClient": "yarn",
-  "registry": "https://registry.npmjs.org/",
-  "useWorkspaces": true,
-  "command": {
-    "publish": {
-      "npmClient": "npm"
-    }
-  }
+  "useWorkspaces": true
 }

package.json

@@ -66,7 +66,7 @@
     "eslint-config-prettier": "^2.9.0",
     "eslint-plugin-prettier": "^2.6.0",
     "husky": "~1.0.0-rc.13",
-    "lerna": "^2.4.0",
+    "lerna": "^3.2.1",
     "lint-staged": "^7.1.0",
     "npm-run-all": "~4.1.1",
     "prettier": "^1.11.1",